Object rendered appears then disappears
ok I found the mistake.
you had the view layer set to coposite, and this means it goes throu the compositor first and then goes to the output,

and when I then look at your compositer you can see that you you selected IndexOB in the Alpha channel, using the viewernode I was able to see that the IndexOB output ist empty (Black) and thus everything was transpatent 

This was an easy fix, I selected the object and added an Pass Index in the Object menu, then in the compositor I added the ID Mask node between IndexOB and the output to select this specific Index

and now the render is as you wanted it to be